The objectives of this cancer control and prevention project are: 1. To design and validate a non-invasive body composition assessment methodology for use in breast cancer risk assessment and for assessing body compositional changes in chemoprevention trials, that will be feasible and accurate for an overweight/overfat population. The specific aims include: a. Part I - Validation Study 1) To recruit 30 women who have never had breast cancer from the Breast Cancer Detection Demonstration Project (BCDDP) Project 23 Long-Term Follow-up Study who were not a part of the BCDDP Wolfe Case-Control Study to participate in this study; 2) To perform a body composition/anthropometric assessment on this population, including anthropometry (height, weight, circumferences, and fat-fold measurements), underwater weight, and impedence measurement; 3) To validate impedence measurement against underwater weighing as an accurate means of assessing total body fat/lean body mass in an overweight adult female population; 4) To analyze results for methodology design for Part II of this study; b. Part II - Cross-Sectional Study 1) To recruit an additional 150 control women, plus 50-75 cases of women who have had breast cancer from the BCDDP Project 23 Long-Term Follow-up who also were a part of BCDDP Wolfe Case-Control Study to participate in this study; 2) To perform the standardized assessment on all 200 women, including anthropometry and impedence measure, as described in a. 2, above. (These women will not be underwater weighed); 3) To perform statistical analyses to determine: a) body composition and b) fat patterns in this population. 2. To determine the relationship between body composition, fat patterning and accepted risk factors for breast cancer (weight, height, parity, duration of menses, breast cancer in a primary relative, benign breast disease, and breast tissue parenchymal pattern). Data accrued in Part II of the study will be analyzed using a logistical regression model to relate specific components of the body composition and fat patterning to known, accepted risk factors for breast cancer.